Seat structure



Nov. 25, 1941. COT HAL 2,264,143

S EAT S TRUCTURE Filed March 22, 1940 2 Sheets-Sheet l INVENTORS LEW/5 M. SCOTT BY ALBERT R. EHRENSPERGER C444; W ATT RNEY.

NOV. 25, 1941; L. M. SCOTT ETAL SEAT STRUCTURE Filed March 22, 1940 jay-4.

2 Sheets-Sheet 2 INVENTORS LEW/5 M. SCOTT ALBERT R. EHRENS PERGER ATTORNEY.

Patented Nov. 25, 1941 UNITED STATES PATENT OFFICE SEAT STRUCTURE Lewis M. Scott and Albert R. Ehrensperger,

New York, N. Y.

Application March 22, 1940, Serial No. 325,320

4 Claims. (01. 155-50) The invention relates to the construction of chairs, sofas and the like, and more particularly to improvements in the design of such articles of furniture for fabrication from molded plastics or from other hard resilient materials.

It is an object of our invention to provide improvements in resilient side frame construction for chairs and the like. One form of chair which is in quite general use today has a frame made of tubular metal in the generalform of a double U having a flat portion adapted to rest on the floor, the forward ends of this flat portion being bent upwardly to form leg supports and then rearwardly to form either arm or seat supports. In this form of chair, there is no direct support at the rear of the chair and resilience is pro vided by flexibility of the tubular elements at thefront of the chair. Generally speaking, this type of chair will flex in direct proportion to the load imposed so that in order to prevent undue strain under a 'heavy load, the chair must be.

made quite stiff, and it consequently'does not afford maximum comfort for a smaller person. Accordingly, it is one of the objects of our invention to provide a construction of the class described which will flex easily under a light load, yet which will not continue to flex in direct proportion to the load but will impose increasing resistance as the load builds up, so as to be comfortable under all conditions of loading and at the same time have greater trength and serviceability. I

A particular object of our invention is to provide an improved chair side frame construction which is especially adapted to fabrication from molded or laminated plastics.

Other objects and advantages will appear as thedescription proceeds.

In the drawings, wherein we have illustrated certain preferred embodiments of the invention,

Fig. l is a side elevational view of a chair con structed in accordance with the pririciplesof our invention. Fig. 2 is an enlarged detail view of a portion of a side frame for such a chair, and Fig- 3 is a cross-sectional view taken on the line 3-3 of Fig. 2. Fig. 4 is a rear elevational view of the chair shown in Fig. 1. I

Fig. 5 is a detail view of another form of side frame embodying the invention. Figs. 6 and 7 are cross-sectional views similar to Fig. 3, illustrating further embodiments of the invention.

Referring particularly to Figs. 1 and 2, we,

have shown a chair comprising a pair of side frame members I and a seat and back member 2 supported from each side frame at two points large radius of curvature.

in such a way as not to interfere with the flexing of the frames. In this connection it should be observed that in certain constructions heretofore proposed in which closed side frames have been employed, the back of the seat has beenseat and back are attached to the frames in such a manner as to take full advantage of this.

'The side frames I are of oval-like configuration, having-a straight lower'portion 3 forming supports near the front and back of the chair for engagement with the floor or the like. The straight lower portion 3. curves'sharplyrupwardly at the frontiand. rear, the' curving portions meeting. Twithout 'chan'gein the direction of curvaturein a flattened upperjportion 4 of relatively 5"adjacent the. front support preferably is of smaller radius than the curving portion 6 adjac'ent the back support. The front I of the loop'extends upwardly and slightly rearwardly at a relatively large radius'of curvature, the general direction of the front portion being such that it forms an angle of less than 90 with the lower portion 3 of the loop. The upper portion 4' and front portion 1 are, joined by a curving portion 8 *which is of relatively small radius 'of curvature. The flattenedportion 4 slopes downwardly toward the rear in' substantial parallelism with the seat portion 9 of the member 2 and is adapted to serve as an arm rest. It will be observed that the'cur'iving part of the loop is formed without re-entrant portions-that isto say,the directionof curvature remains the same throughout itsentirelength'this being essential to securethe. maximum benefits of our invention. From" the forward-end of the straight portion 3 theloop extends upwardly and rearwardly in one unbroken curve to'the back support or to the pointwhere it joins the rear of the straight portion 3. The form of this loop might be described as that of a streamlined oval," and this form possesses particular advantages when the seat and back member is supported from the side members in the manner to be described.

The back portion-l0 of the member 2 is supported from the flattened upper portion of each In such constructions the re-" The curving portion provided by direct engagement of the back with the portion 4 of each side member I, or suitable attaching means such as brackets or a supporting rod may be employed. In the embodiment illustrated in Figs. 1 and 4, a brace ll extends between the side frames 1, being attached thereto in any suitable manner as by means of the brackets l2. The back l0 may then be secured in fixed relationship to the brace II, or these two elements may be adjustably secured together as by means of slotted brackets 13 secured to the back It), and wing screws or bolts M which slidably engage the slots of the brackets l3 and pass through the brace ll whereby the member 2 can be securely held in any one of a number of selected positions of adjustment with respect .to the side frames I. In this connection it will be observed that whereas we have shown a seat and back member 2 which is adapted to be made of metal or plywood, this member'might be upholstered if desired, in which case it would" be dropped into a lower positionwith reference to the side frames withoutchanging the essential design of the seat or the manner of its support on the frames. The forward end of the seat is attached to the portion 1 of'each side frame in a manner similar to that which has been described with reference to the attachment of the back I0, or in any other suitable" manner. The seat 9 preferably extends forwardly of the portions 1 and is turned downwardly and rearwardly as at M for connection to the side frames l at the point 15. If desired; a brace similar to thebrace ll may be provided underneath the seat at the point It.

The side frames I may be formed of any :suitable resilient material, but preferably are-formed of a plastic composition either by cold molding or compression type molding. Plastic compositions afford unlimited color selection, may be transparent, translucent or opaque, and are resistant to cigaret burns-and'stains, alcohol'and other substances harmful to wood or metal;

Moreover, plastics are resistant to warping and shrinking, and can be fabricated to afford the desired resiliency for our novel form of side frames. These frames may be molded in solid or hollow form, or they may be built up of separate laminations bonded together under heat and pressure. The laminations themselves may be made of plastic substances, or they maybe made of wood or other material impregnated and bonded together with a viscous resin under heat and pressure. Such a laminated construction is illustrated in Figs. 2 and 3 wherein it will be seen that the laminations I! are put together in staggered relationship so that the meeting ends in each layer are offset with respect' to the meeting ends of adjacent layers. Thus the joints l8, l9 and 20 are offset with respectto one another. The sharper bends inthe frame may be reinforced by providing an extra lamination or laminations at any point where greater strength or stiffness is desirable. Such an extra lamination will be seen at H in Fig. 2.

Fig; illustrates a modified form of side frames 22' inwhich the sharply curving rear portion 23 is made of a thickness greater than that of the remainder of the frame to provide increased resistance to bending stresses at this point. This is applicable to either a solid or laminated construction.

The side frames may be of any desired crosssectional form such as square, rectangular, round,

half-round or oval. It is preferable, however, that the cross-section be such that it is of relatively shallow depth in the plane of the loop in order to provide proper resiliency.

A preferred cross-sectional form is shown in Fig. 6, this form being generally rectangular or channel-shaped. The beads or flanges 24 increase the apparent depth and also the strength while minimizing the amount of material used in the construction. The form shown in Fig. 7 is similar to that of Fig. 6 except that it is hollow, thus making the chair lighter in weight and further economizing on the amount of material required in the construction. Other modifications will suggest themselves to those familiar with plastics or with furniture design. Where hollow forms are used, the frames may be molded in tumor more'pieces to facilitate coring, the separate pieces being fused together under heat and pressure after the molding operation has been completed. If extrudible materials are employed, the hollow sections may be extruded in any desired length in the form of a straight bar which may then be cut up into lengths equal to the perimeter of the side frame and'bent into the oval-like configuration illustrated in Fig. l, the meeting ends being fused together or otherwise secured to form a continuous loop.

When the frames are to be made of solid construction with molded plastics, the plastic material is softened by heat and is then molded either in the final form of the frame or in a form which later may be shaped and hardened by suitable heat treatment. When the frames are to be made of laminated plastic construction, thev laminations are impregnated with a resinous composition and arethen subjected to pressure in a special press, die or form, generally with the application of heat, until the bonding action is complete.

An important feature of our invention resides in the beam action of the upper section 4 of the closed loop of the side frame which results in distribution of the stress and builds up the resistance to flexing of the frames very rapidly as the load reaches a. predetermined amount. This action is illustrated in Fig. 1 in which the dot-dash lines show an approximation of the form assumed by the side frames under certain conditions of loading. It will be observed that the upper flattened, portion 4 is depressed, witha tendency to increase the radius of curvature thereof whereas the front portion 1 is inclined slightly more toward the rear, decreasing the angle which it makes with respect to the lower portion 3. The increase injthe radius of curvature of the upper portion 4 is most apparent in line with the point of attachment of the back ID to the frames. There may be some decrease in the radius of curvature of the portion 8 of the loop although this is so slight as to be scarcely noticeable. There will also be a slight decrease in the radius of curvature of the sections 5 and 6 as will be seen at 5' and 6' although if the section 6 is reinforced in the manner indicated at 23 in Fig. 5, the decrease in the radius of curvature at this point will be negligible. With this construction, the resilience is provided almost entirely by what may be described as the beam action of the upper section 4 which, in moving to the position shown at 4', decreases in curvature (i. (2., becomes of increased radius of curvature). This is in contrast to open frame constructions in which flexing is accomplished primarily by decreasing the radius of curvature in the forward part of the frame where all of the stress is concentrated within a limited region. In our construction, the flattening of the oval under load distributes the stress over the entire curved part of the frame. This permits the frames to be made of quite a high degree of resilience without sacrifice of needed strength so that the chair is comfortable for small persons. Yet when a large person uses the chair, the resistance builds up very rapidly as the upper portion 4 is depressed.

While throughout the foregoing description we have referred primarily to chair construction, it will be understood that the invention is applicable as well to sofas and other articles of furniture. The terms and expressions which we have employed are used as terms of description and not of limitation, and we have no intention of excluding such equivalents of the invention set forth, or of portions thereof, as fall within the purview of the claims.

We claim:

1. A seat structure comprising a pair of side members and a seat and back member supported thereon, each side member consisting of a resilient element in the form of a continuous closed loop smoothly curved convexly throughout and having a flattened upper portion.

2. A seat structure comprising a pair of side members and a seat and back member supported thereon, each side member consisting of a resilient element in the form of a continuous closed loop having lower portions arranged to form supports near the front and back of the seat for en gagement with the floor or the like and having a portion extending upwardly and rearwardly from the front support in one unbroken curve to the back support, said curve being smoothly convex throughout.

3. A side frame for seat structures which consists of a resilient closed loop smoothly convexly curved throughout of molded plastic having a flattened top portion, said loop having a hollow substantially rectangular cross section of relatively shallow depth in the plane of the loop to provide resiliency.

4. A seat structure comprising a pair of side members and a seat and back member, each side member consisting of a resilient element in the form of a continuous closed loop of oval-like configuration, said loop having an open center, said seat and back member being attached to the upper part of said side members in a manner to produce flattening of the oval under load.

LEWIS M. SCO'I'I. ALBERT R. EHRENSPERGER. 

